1. Field
These inventions relate to irradiation devices and methods, including for example, UV curing apparatus and methods and hand-held UV curing apparatus and methods.
2. Related Art
UV curing apparatus and methods are used for curing photo-initiated adhesives and other coating compositions. UV radiation curing offers significant energy and savings compared to thermal curing in heat ovens. UV radiation curing also is much quicker with significant time savings, and is more environmentally friendly in reducing toxic emissions. Another advantage of UV curing is the adhesives leave behind no solvent residue, as is common with thermoplastic adhesives which set upon cooling or evaporation of a solvent. U.S. Pat. No. 6,000,815, and U.S. published patent publication U.S. 2004/0165391, each discuss irradiation lamp assemblies. The descriptions and drawings of those documents are incorporated herein by reference.
In these apparatus, the lamp source is positioned inside the reflector so that UV radiation produced by the lamp source when energized irradiates the target surface or material. Part of the radiation is emitted directly from the lamp source toward the target, while part of the radiation is focused onto the target by the reflector. Any focus on the target depends on the reflector configuration, the lamp source configuration and its orientation relative to the reflector.
Existing lamps generally have a single mode of operation. For example, a linear lamp source combined with a longitudinally extending reflector can be used to produce a line of radiation for curing material. The assembly, for example, can be used to cure a coating on a wall, such as by passing the assembly back and forth over the surface. Substantially all of the coating on the surface can be cured in this way, but curing surface coatings in a corner of two adjacent walls or in a corner between two walls and a floor or ceiling may be more difficult. The ease of curing surface coatings in a corner of two adjacent walls will depend on the resolution or how fine the beam of radiation is from the assembly. With a finely focused beam, a corner area can be cured without inadvertently over-irradiating adjacent surface material.
In a corner between two adjacent walls and a floor or a ceiling, it is more difficult to cure the corner material without over-irradiating the adjacent surface material. For example, because the corner is an intersection of three surfaces rather than two surfaces, irradiation from a linear beam for a given lamp assembly extends not only into the corner but also along adjacent wall surfaces. As a result, the adjacent wall surfaces may get more radiation than the corner before the corner surfaces are properly cured. Additionally, equipment design is such that equipment parts such as housing components, reflector parts and the like extend around the sides of the lamp source, making it more difficult to place the lamp source as close to the surface as may be desired for adequate curing.
When the lamp source produces radiation, the lamp source temperature increases and generally requires cooling for the desired continued operation. Additionally, radiation reflection from the reflector raises the reflector temperature, which should also be cooled. In one configuration, one or more fans draw outside cooling air into the reflector trough and around the irradiation lamp source, thereby cooling both.